This invention relates to a hollow granular medicine and its preparation, and more particularly, but not exclusively, to a granular medicine having a spherical structure and slow drug-release characteristics.
Oral drugs, which are promptly absorbed in the alimentary canal and are also rapidly lost from the blood, are generally film-coated or microcapsulated to cause the slow drug-release. These techniques, however, only delay the drug release and hence have a problem: while a drug can only be absorbed in the upper portion of small intestines, the drug might be released from a capsule or a pill after passing the absorption site. Even if slow drug release is attained, the drug that is released after passing the absorption site is not utilized, thus lowering the efficacy of the drug.
A drug whose solubility varies with pH generally differs between individuals in the incidence and duration of the effect. When the drug is treated to cause the slow drug release, it differs even more. Examples of such drugs include ibuprofen, ketoprofen and tranilast.